The armed Basque separatist group Eta today announced a ceasefire, raising hopes of a new peace process with the Spanish government but giving few clues about how that might happen.

The announcement was made in a video showing three masked Eta militants sitting behind a table with the group's axe and snake symbol behind them.

"Eta announces that it took the decision several months ago not to carry out armed actions," one of the militants, a woman, said.

The group has killed more than 800 people in a 50-year campaign for an independent state made up of four Spanish provinces and part of south-west France.

The masked figures in the video said Eta wished "to reach a scenario for a democratic process", but failed to indicate whether the ceasefire would be temporary or permanent.

The message also made no mention of either giving up arms or an international verification process – something experts have said would be key to any future peace process.

There was no immediate reaction from Spain's socialist government, which was expected to make a public reply.

The Eta announcement comes after six months in which the group has not killed anyone.

The last killing carried out by Eta – classed as a terrorist organisation by the EU and the US – was of a French police officer who discovered members stealing cars from a dealership outside Paris in March.

The last fatal attack in Spain saw two police officers killed on the holiday island of Majorca in July 2009.

It is not the first time Eta has unilaterally declared a ceasefire. The last ceasefire, which it described as "permanent", was announced in March 2006 and saw prime minister José Luis Rodríguez Zapatero's government enter into talks with the group.

Zapatero had said, the day before the blast, that he was optimistic about the process.

The bombing was seen as proof that an internal battle between the hawks and doves in Eta had been won by the former.

Eta's 40-year campaign for independence in the Basque region has seen 800 people killed

Police have since arrested many of the group's senior leaders, and it is not clear who now runs it. The fact that today's communique was read by a woman supports claims that several women are now near the top of Eta's command structure.

Spanish government sources have been sceptical about moves by former leaders of Batasuna, a party banned for being an Eta front, to reopen a peace process in recent months.

Some Batasuna leaders now believe the low-level terrorism practised by a much-weakened Eta in recent years is ineffectual and an impediment to progress towards independence.

They have been putting pressure on Eta to lay down arms since a public appeal was made in February.

In a document shown to the Diaro Vasco newspaper over the weekend, senior Batasuna members mapped out a path to peace that included "a permanent ceasefire with international verification".

That echoed a call made in March by a group of international peace experts, who advised Eta to follow the new path to peace being signalled by former Batasuna leaders.

The call was made by, amongst others, the Nobel peace prize winners John Hume, Desmond Tutu and FW de Klerk. It also had the backing of the Nelson Mandela Foundation.

But government sources have said the influence of former Batasuna leaders on Eta is weak and the previous ceasefire had shown they had no control over the terrorist group.

The militants on today's video accused the Spanish sate, which does not recognise a right to Basque independence, of carrying out a "fascist offensive" against the Basque country.

"The Spanish state is aware that the Basque country is at a crossroads, that the Basque country can now take the road of independence," they said.

"They want to create conditions in which everything is blocked, to avoid political dialogue and drown out the aspirations of the people."